Update - I reached out to the seller regarding my issues and they offered to send me a replacement. I have now had the new one for a week. Old watch showed no apnea via app. New watch shows supposedly 42 apnea events in one night, even though hubby says I don’t snore, I’m a side sleeper and some events supposedly occurring when I was in bed reading my Kindle or trying to fall back asleep in the morning. So take these readings with a grain of salt. The only real way to test for sleep apnea is to be evaluated at a sleep clinic. Everything else appears to be in a normal range.Revised review #3 - So far so good. It has been working normally. I’m not sure why it stopped functioning previously. Could be an app issue? I’m prepared to do more troubleshooting or reset or factory reset or if any future problems arise.Revised review #2 - So I decided to do more troubleshooting before giving up on this tracker. I used a soft cloth to clean off the sensors. Didn’t work. So that was not the problem. Then I went into the app and did a factory reset on the tracker. Now it’s recording BP and heart rate. I’ll see how well it tracks my sleep tonight. I don’t use notifications so I can’t comment on that. I only use this watch as a fitness/sleep tracker.Revised- I’ve had this tracker for a month now and it has recently begun incorrectly recording my sleep duration. I’ve tried troubleshooting by unpairing from the app, turning Bluetooth off and back on. The blood pressure and heart rate have recently stopped recording every 5 minutes as they are supposed to. Same troubleshooting techniques used for this problem. Sometimes it works, lately not. I even cleaned the sensors in case that was causing the problems. The only thing that seems to be still working correctly is the step counter. Very disappointing as I had hoped this tracker would last much longer than a month. I’m going back to my old 5-year-old Fitbit Charge 2. At least it still works. I’ll use a blood pressure cuff for my BP readings. More reliable.Original review- It seems to do everything at a fraction of the cost of some name brand smart and fitness watches. The accompanying H Band app is very easy to navigate. I did notice, however, after reviewing my last night’s sleep that it showed me as sleeping for an hour when in fact I was in bed reading my Kindle. It also showed me waking up at 7 a.m. when in fact I slept until 9 a.m. It has been accurate up until then. Not sure what happened there. I do like all of the features and BP and heart rate seem pretty accurate. I love being able to do an ECG but I don’t know how accurate it is as I’m not in the medical field. All in all I am pretty happy with my tracker. I’ll have to see how long it lasts. I have an old Fitbit Charge 2 that is 5 years old and still works. I don’t know the shelf life of the Gogum tracker as compared with Fitbit. But the price was attractive to me and I decided to give it a try. It’s hard to find trackers that record BP, blood oxygen levels and ECG. Most only track steps and sleep. This little watch does it all. It also tracks light sleep, deep sleep and REM sleep. Very nice.For some reason a couple of times the app shows my wake up time as 6:55 when in fact it was 8:35. So this is a problem.The 1st one I bought the band came off while I was wearing gloves & loading up my truck. One of the part of the band that connects to the watch popped off when I was sliding my arm threw a narrow area and I didn't realize it. So someone found themselves a watch. The second one I got I have beenp mindful about making sure it doesn't snap off. The band pisses me off when trying to take it off. Everytime I pull it a little tighter so I can get it off the little metal bar goes into the next hole. It almost cut my circulation off from doing this. I really don't like the band design, however I picked it bc it was 1 of the few fitness tracker watches that doesn't have a fat band. It has never tracked my temperature the entire time I've had it. It doesn't even have an area to check my temperature manually like the BP, pluses, O2 levels, and EEG. The pulse runs a little high by maybe 5 points but the BP runs very, high. My BP actually is running high which it did let me know but it was not as high as the watch indicated by 10 points for the top # and 20 points for the bottom. The EEG seams to be about right but it has to be manually done where the BP,O2, heart rate are automatically tracked 24/7. It offers some info on terminology on sleep issues that one might find out they have and the same with the heart health index doesn't make sense and offers no information on why some categories are 1-5 stars. I don't know if 1 star means there's nothing to worry about or if I need to get it checked out quickly. The app also also allows for notifications from almost any app on your phone. The notification pops up but barley stays on long enough to read but I have never been a fast reader. I find the other app anoying as it's constantly vibrating and just shows a picture of a heart. It doesn't let me know if it's my pulse or BP. You go and set what your normal BP & pulse usually run and it will let you know if it starts to run high. Its battery life is not as good as I was hoping however it does charge quickly But it is picky about what USB charger it will use. One seamed to work then just stopped working I had to go through several other USB charger I have to find one that will work. It's better then nothing but I want a better and more accurate one as I have an autoimmune condition that has affected my heart & I need something that will monitor my pulse and BP w more accuracy. I thought this watch would and track my body temp because they believe it's starting to affect my autonomic nervous system might and I like that it tracked sleep. It does do a great job tracking sleep, as I have a tendency to go into deep sleep quickly (as stated by a sleep study) and stay in it longer then usual. I would recommend shopping around for another watch that offers what your looking for, I think I picked this one based on price & shouldn't have.